| 摘要 |
PROBLEM TO BE SOLVED: To suppress deterioration in luminous efficiency of each LED.SOLUTION: A substrate 10 is made of copper. A plurality of LEDs 11 are densely arranged by having their rear surfaces directly attached on a first surface being one surface of the substrate 10. A cooling tower 2 is provided in contact with a second surface being the other surface of the substrate 10 and cools the substrate 10. The plurality of LEDs 11 are directly attached to the first surface of the substrate 10 having thermal conductivity equal to or higher than a predetermined level, and the substrate 10 is in contact with the cooling tower 2. Thus, heat generated from the LEDs 11 can be efficiently released to the cooling tower 2. |
